1. Technical Field
The present invention relates generally to improved data security and in particular to a method and an apparatus for invoking a secured method for rendering data. Still more particularly, the present invention provides a method and an apparatus for detecting the need for data security and selecting an appropriate means for presenting the data in a secured manner.
2. Description of the Related Art
Digital communications occurs in a wide variety of environments and with many different types of devices. Some devices, such as a cellular telephone or a wireless personal digital assistant (PDA), are used in different ambient environments, many of which might be unsecured for accessing sensitive data. Other devices, such as desktop computers, are typically in a fixed location where the environment is relatively stable. However, even in this situation, the environment may be changing due to different people being able to view a computer screen or being able to hear voice communications.
Data encryption is commonly used to provide data security when the data is being transferred over a network. There are a variety of encryption techniques. Data Encryption Standard (DES) is based on use of a symmetric private key with the level of security varying according to key length, typical lengths ranging from 56-bit DES to 256-bit DES. Public key cryptography, also called the RSA method, named after the inventors Rivest, Shamir, and Adleman, uses an asymmetrical key pair in which one key is public and the other key is private. Data is typically encrypted by using the recipient's public key, and can only be decrypted by using the recipient's private key. The roles of the two keys can also be reversed, such as digitally signing a document using the sender's private key, and validating the signature using the sender's public key. RSA is very computation intensive, thus it is often used to create a digital envelope, which holds an RSA-encrypted DES key and DES-encrypted data. This method encrypts the secret DES key so that it can be transmitted over the network, but encrypts and decrypts the actual message using the much faster DES algorithm. A related invention, U.S. patent application Ser. No. 09/240,387, describes a method and apparatus for selecting encryption levels based on policy profiling.
After data is received at the destination, it is decrypted and presented to the user. This presentation is typically visual, audio, or a combination of rendering methods. The data is no longer secured at the time of rendering and, if the ambient environment in unsecured, others may gain access to the data. For example, others may hear a voice mail played back in a public environment. Therefore, it would be advantageous to use a secured means of rendering so that only the intended recipient can receive sensitive information even if the information is presented in an unsecured environment.